Connectors for fluid transport are common and widely used. Typically, such connectors often employ a female coupling that connects with a male insert member. These couplings provide a structure that can be readily coupled and uncoupled from a male insert member using a quick connect/disconnect configuration. To achieve this quick connect/disconnect configuration, a latch mechanism usually is incorporated with the coupling. Such mechanical latches provide a releasable lock mechanism for connecting and retaining a male insert member to the coupling, so that sealing surfaces of a coupling and male insert member remain in contact for a fluid tight seal.
Incorporated herewith by reference, U.S. Pat. No. 5,033,777 to Blenkush discloses one example of a latch mechanism 40. The latch mechanism 40 includes a latch plate 80 that is slideably mounted in grooves formed by two projections 82 extending from the front of a female coupling assembly 14. The latch plate 80 is slideably mounted for transverse movement with respect to a bore 30 of the female coupling assembly 14 between a first released position (FIG. 4) and a second latched position (FIG. 5). The latch plate 80 defines an annular aperture 84 therein. In the released position, the tubular portion 18 of a male insert 12 can be inserted through the aperture 84 and into the bore 30. In the latched position, an inner edge of the latch plate 80 moves into a groove 24 of the male insert 12, thereby positively latching the male insert 12 with the female coupling assembly 14 in a coupled state.
A housing of the female coupling assembly 14 defines a recess of indentation 90 proximate its top portion and between the projections 82. The latch plate 80 includes a lever portion 80a that is folded over so as to provide a relatively flat lever. The lever portion 80a fits in the recess provided by the indentation 90. A coiled spring 92 is positioned between the lever portion 80a and a bottom surface of the indentation 90. The coiled spring 92 biases the latch plate 80 transversely of the bore 30 and toward the latched position.
A locking pin 94 having a varying diameter axially extends from a bore 96. The locking pin retains the latch plate 80 in its released position when the male insert 12 and the female coupling assembly 14 are in an uncoupled state. The bore 96 is positioned radially outward from the bore 30 and on an opposite side from the lever 80a, so as to be diametrically opposed to the lever 80a. The locking pin 94 extends through a slot of the latch plate 80 having a variable width defined by edges 98a and 98b. The edges 98a, 98b extend radially outward from the inner edge of the aperture 84. The locking pin 94 is longitudinally moveable through the slot between a first position wherein the locking pin 94 allows the spring 92 to move the latch plate 80 into its latched position. The locking pin 94 in its second position also serves to limit the distance, which the latch plate 80 moves from its released position to its latched position. A coiled spring 100 is positioned between a collar portion 94a of the locking pin 94 and an end of the bore 96, so as to longitudinally bias the locking pin 94 toward the first released position.
The male insert 12 includes a collar 102 about the circumference thereof which is spaced a predetermined axial distance from the groove 24 toward the second end 28 of the male insert 12. The collar 102 is constructed and arranged to engage the locking pin 94, as the tubular portion 18 is inserted into the bore 30 of the female coupling assembly 14 a predetermined distance, such that the locking pin 94 is pushed back from its first position into its second position.
The radially extending edges 98a are spaced farther apart than edges 98b. In this configuration, the slot has a portion defined by edges 98a near the inner edge of the aperture 84 having a greater width than the portion defined by edges 98b near the end of the slot and farthest removed from the inner edge. When the locking pin 94 is in the first released position, a portion 94b of the locking pin 94 having a greater diameter than the width of the slot defined by the edges 98b, extends through the slot defined by edges 98a. The locking pin portion 94b makes contact with edges 98b, and prevents the latch plate 80 from being moved into the latched position by the coil spring 92. As the male insert 12 is inserted into the female coupling assembly 14, the collar 102 engages the end of the locking pin 94 and moves it longitudinally relative to the female coupling assembly. The locking pin moves into the bore 96 until a portion 94c of the locking pin 94 having a diameter less than the width of the slot defined by the edges 98b aligns therewith, such that the locking pin 94 no longer engages the edges 98b. The latch plate 80 then moves into the latched position by the coil spring 92 and engages the groove 24.
By pressing radially inward on the lever 80a, the latch plate 80 is caused to move radially such that the locking pin 94 extends through the enlarged slot edges 98a near the inner edge. The latch plate 80 can then be disengaged from the groove 24, whereby the male insert 12 can be removed from the female coupling assembly 14. When the male insert 12 is removed, the collar 102 and the locking pin 94 are disengaged whereby the spring 100 biases the locking pin toward its first position, so that the pin portion 94b engages the edges 98b of the slot and retains the latch plate 80 in its released position.
The latch plate of the latch mechanism above, however, may still experience problems in reliability and performance. As the latch plate provides its slot continuously extending from the annular aperture where the inner edge is directly adjacent the slot, sharp burrs and corners exist that can comprise sealing surfaces of a connecting male insert. Such surfaces can include resilient o-rings or part line free sealing surfaces disposed about the collar of the male insert, and that sealingly engage with the inner surface defined by the bore of the female coupling assembly. Further, the latch plate above includes an inner edge that corresponds to the radial perimeter defined by the annular aperture. Where increased pressures are used, such as up to 100 psi, a connecting male insert may rotate and/or twist relative to the female coupling. In this configuration of an inner edge, the male insert may unfavorably cam out and become separated from the female coupling assembly during use.
While the above design may be suitable for its intended purposes, improvements may still be made upon the latch mechanism structure of such couplings. Therefore, there is a need for a latch mechanism with a latch plate having improved reliability and performance. A coupling is desired that provides a latch plate that prevents separation when connected with a piece of fluid transport equipment, such as a connecting insert, and that protects sealing surfaces of a connecting insert from being damaged.